Printing services Web sites allowing a user to access the site from a computer located at the user's home or work and design and purchase an item of apparel, such as a t-shirt or other item, are well known and widely used by many consumers and businesses. Typically, these printing services sites allow the user to first review uncustomized images of the various products that are available from the provider. When the user selects a specific product to customize, the sites typically provide online tools allowing the user to provide the text that the user desires to appear on the customized product. The user is also typically allowed to either upload a full color image from the user's computer to be incorporated into the product design or select from a number of decorative designs, images, and other graphic elements that are provided for the user's use by the printing services provider. Images of the user text entries and the user-selected decorative elements, collectively referred to herein as “design images” are combined with the basic product image to create a composite image indicating the appearance of the printed product. When the design is completed to the user's satisfaction, the user can place an order through the site for production of a desired quantity of the corresponding printed product using a commercially available computer-to-textile printing system.
To avoid customer disappointment, it is desirable that the image of the product that is displayed to the customer on the customer's computer display be a substantially accurate representation of the physical product that the user will later receive. Trying to faithfully represent the appearance of printed areas can be a problem because the appearance of the printed image may be affected by the color of the surface on which the image is printed. In the field of printing designs onto apparel, some printing systems are particularly adapted to print designs on dark materials. These systems typically first print a layer of white ink and then print the design on top of the white ink layer. This process results in a faithful color reproduction of the design, but such systems are typically more expensive to purchase and operate. The system itself contains additional white ink printing components, additional white ink is required, the printing process is slower because of the extra printing steps, and the drying time is longer because of the additional ink that is applied.
Other printing systems are particularly adapted to print designs on very light materials. These systems typically use only color inks, with any white areas in the design being treated as transparent. Because no ink is applied in the white areas of the design, the underlying material is visible. This type of system is typically less expensive to buy and operate than the dark material printing system, is capable of producing more units over the same period of time, and requires less product drying time. When this type of printing system is used to print a design onto white material, the customer receives a printed product that is generally substantially similar to the image displayed to the user on the user's computer system at the time the product was being ordered. However, if this type of printing system is used to print a design onto a material that is gray or another non-white color, the color of the material often affects the appearance of the design on the material, especially in areas of the printed design that are printed in lighter colors. For example, an image having areas of lighter colors that is printed on a white t-shirt will not have the same appearance as the same image printed on a gray t-shirt.
To minimize the risk of customer surprise and disappointment when the printed product is delivered, it is desirable that the customer be shown an image of the product during the product design and ordering process that is as accurate a depiction of the physical product as practical. A technique for design image processing involving only the modification of the alpha values of design image pixels is disclosed in co-pending and co-assigned application Ser. No. 11/735,838 filed Apr. 16, 2007 and entitled “Representing a Printed Product Using Image Blending”.